JP2002277711A - Lens barrel and camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the possibility that the cam follower part of a lens holding barrel comes off from the cam groove part of a cam barrel when impact in an optical axis direction is applied to the lens holding barrel due to drop or the like. SOLUTION: This lens barrel is provided with the lens holding barrel 21 holding a lens 18, the cam barrel 16 provided with the cam groove part 16c engaged with the cam follower part 21a formed in the lens holding barrel and giving driving force in the optical axis direction to the lens holding barrel, and a guide barrel 17 provided with a straight advance guide groove part 17d engaged with a straight advance key part 21b formed in the lens holding barrel and guiding the lens holding barrel in the optical axis direction. The lens holding barrel is provided with the cam follower part and the straight advance key part side by side in a lens barrel diameter direction, and the straight advance key part and the straight advance guide groove part are formed to have shape that the movement of the cam follower part to the cam groove part in the lens barrel diameter direction is restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel and a camera, and more particularly to a countermeasure against an impact of an extension type lens barrel.

[0002]

2. Description of the Related Art The basic structure of an extension lens barrel is as follows.
As disclosed in Japanese Patent Application Laid-Open No. 2000-194046 and the like, a so-called differential feed-out mechanism that feeds lens barrel constituent members on the inner and outer circumferences of the differential tube and the straight movement restricting member by relative rotation of the differential tube and the straight movement restricting member. There are many.

FIG. 4 to FIG.
1 shows a configuration of a digital camera using a differential extension lens barrel proposed in Japanese Patent No. 94046 or the like. In addition,
FIG. 4 shows a use state of the camera (extended state of the lens barrel), and FIG. 5 shows a non-use state of the camera (state of collapsed lens barrel). 6 shows a cross section taken along the line AA of the first-group holding barrel pin portion 121a in FIG. 4, and FIG. 7 shows a state where an impact is applied to the first-group holding barrel 121 from the optical axis direction. .

In FIGS. 4 to 7, reference numeral 101 denotes a camera body. The camera body 101 is covered with an operation member (not shown) and an exterior member 103 having a liquid crystal display device 102.

The camera body 101 includes a finder block 104, a hard board 105 having a circuit including electric elements, a battery (not shown), a recording device (not shown),
A strobe (not shown) and an extension lens barrel 106 are held.

The construction of the extension lens barrel 106 in such a digital camera will be described.

Reference numeral 107 denotes a CCD as an image sensor, and reference numeral 108 denotes a low-pass filter, each of which is fixed to a base 109.

A base 109 is provided with a third group holder 111 for holding a third group lens 110, and a lens feeding mechanism 112 including a step motor and a screw feeder. The third group is operated by the operation of the lens feeding mechanism 112. Driven in the optical axis direction.

Reference numeral 113 denotes a fixed cylinder having a cam groove 113a and a straight key groove 113b formed on the inner periphery thereof. The fixed cylinder 113 is fixed to the base 109.

Reference numeral 114 denotes a drive ring fitted around the outer periphery of the fixed cylinder 113 and rotated around the optical axis. This drive ring 114 is
A lens barrel driving device including a lens barrel motor and the like (not shown) connected to a gear portion 114a provided on the outer periphery thereof, and a gear train 1
15 is driven to rotate. Further, the drive ring 114 is
It has a drive key groove 114b on its inner periphery.

A cam cylinder 116 is provided on the inner periphery of the fixed cylinder 113. A cam pin 116a that engages with the cam groove 113a of the fixed cylinder 113 is provided on the outer periphery of the cam cylinder 116.
And a drive pin 116b that engages with the drive key groove 114b of the drive ring 114. A first group cam groove 116c and a second group cam groove 116d are formed on the inner periphery of the cam cylinder 116.

When the drive ring 114 rotates, the cam cylinder 1 is engaged by the engagement between the drive key groove 114b and the drive pin 116b.
16 is driven in the optical axis direction along the cam groove 113a while rotating.

Reference numeral 117 denotes a rectilinear cylinder fitted on the inner periphery of the cam cylinder 116. The rectilinear cylinder 117 has a rectilinear key portion 117a which engages with the rectilinear key groove 113b of the fixed cylinder 113. Further, the straight barrel 117 has the cam barrel 116 sandwiched in the optical axis direction by the bayonet claws 117b and the flanges 117c provided at both ends in the optical axis direction. Move without rotating in the axial direction.

The straight-moving cylinder 117 is provided with three first-group straight-moving key grooves 117d penetrating the cylinder main body and three second-group straight-moving key grooves 117e penetrating the cylindrical main body.

Reference numeral 119 denotes a lens barrier that protects the first lens group 118 when the lens barrel is housed, and 120 denotes a barrier drive device that drives the lens barrier 119 to open and close. These lens barrier 119 and barrier driving device 120
It is fixed to the front end of the group holding lens barrel 121.

The first lens group holding barrel 121 is connected to one of the cam barrels 116.
Three pin portions 121a engaging with the group cam groove portion 116c
And three straight key portions 121b that engage with the first group straight key groove portion 117d of the straight cylinder 117. Since the first-group holding lens barrel 121 is allowed to move only straight by the straight-moving barrel 117, it is driven along the first-group cam groove portion 116c without rotating with respect to the camera body with the rotation of the cam barrel 116, It moves forward and backward with respect to the cam cylinder 116 in the optical axis direction.

Reference numeral 122 denotes a second group lens, and a second group holder 1
25. Also, in the second group holder 125.
Shutter blade 123 and shutter driving device 124
Is attached.

The second group holder 125 is urged radially outward by an urging spring 126 to engage with two cam pins 125a (not shown) which engage with the second group cam grooves 116d of the cam cylinder 116. Urging pin 12 pressed by 116d
7 and a linear key portion 125b that engages with the second group linear key groove portion 117e of the linear cylinder 117.

The second group holder 125 is allowed to move only in the optical axis direction by the second group straight key groove 117e.
The cam barrel 116 is driven along the second group cam groove 116d without rotating with respect to the camera body with the rotation of the cam barrel 116, and advances and retreats with respect to the cam barrel 116 in the optical axis direction.

A lens barrel driving device such as a lens motor (not shown), a lens feeding mechanism 112 and a shutter driving device 124 are electrically connected to the circuit of the hard board 105 via a flexible printed board 128.

In the digital camera using the differential lens barrel constructed as described above, when the operating member of the exterior member 103 is operated from the non-use state shown in FIG. The lens barrel driving device is controlled by the driving ring 114, and the cam ring 116 and the first group holding lens barrel 121 are driven forward and backward in the optical axis direction by rotating the drive ring 114, and the second group holder 125 is moved in the optical axis direction. Roll out. Further, by controlling the lens extension mechanism 112, the third group lens 110 is driven, and the optical system is configured as shown in FIG.
Place in the use condition shown in.

When a release operation is performed in a use state, A
Exposure, image processing, and recording operations are performed by performing F and AE operations.

[0023]

In the lens barrel or camera described above, when the camera shown in FIG. 4 is in use, a drop or the like causes an impact in the optical axis direction on the first group holding barrel 121 (arrow in FIG. 7). (Shown in FIG. 6) because the pin portion 121a of the first-group holding lens barrel 121 escapes along the slope of the first-group cam groove portion 116c of the cam cylinder 116 to the inner periphery as shown in FIG. As shown in FIG.
a is disengaged from the cam groove 116c.

Therefore, the present invention provides a lens barrel and a camera in which a cam engaging portion is not easily disengaged by an external force applied to the lens barrel in the direction of the optical axis in a lens barrel of the extension type. The purpose is.

[0025]

In order to achieve the above object, the present invention provides a lens holding cylinder for holding a lens,
A cam cylinder provided with a cam groove that provides an optical axis direction driving force to the lens holding cylinder by engaging with a cam follower provided on the lens holding cylinder, and engages with a straight key portion provided on the lens holding cylinder. A lens barrel having a guide cylinder provided with a linear guide groove for guiding the lever holder in the optical axis direction, wherein the lens follower includes a cam follower and a straight key part. The straight-moving key portion and the straight-moving guide groove portion are formed in a shape that restricts the movement of the cam follower portion in the lens barrel radial direction with respect to the cam groove portion.

Accordingly, even if an external force in the optical axis direction acts on the lens holding cylinder to move (disengage) the cam follower portion in the lens barrel radial direction with respect to the cam groove portion, the movement of the straight key portion and the straight guide groove portion is restricted. The detachment is reliably prevented by the action, and a lens barrel resistant to impact can be realized.

Specifically, for example, a claw-like portion protruding in the lens barrel circumferential direction is formed in the straight-moving key portion, and the claw-like portion is engaged with the lens barrel circumferential direction end face of the straight-movement guide groove in the lens barrel radial direction. A rail portion that can be combined and extends in the optical axis direction is formed.

By forming the engaging surface between the claw-shaped portion and the rail portion so as to be a tapered surface when viewed in the optical axis direction (that is, the cross section orthogonal to the optical axis), the lens holding surface is formed on the engaging surface. It is possible to also serve as a guide surface in the optical axis direction of the cylinder, and it is possible to reliably prevent the above-mentioned disengagement without impairing the function as the original straight guide groove.

[0029]

1 to 3 show the configuration of a digital camera using an extension type lens barrel according to an embodiment of the present invention.

FIG. 1 shows a use state of the camera (barrel extension state), and FIG. 2 shows a non-use state of the camera (barrel collapse state). FIG. 3 shows a BB cross section of the first-group holding barrel pin portion 21a in FIG.

1 to 3, reference numeral 1 denotes a camera body. The camera body 1 is covered by an exterior member 3 having an operation member (not shown) and a liquid crystal display device 2.

The camera body 1 comprises a finder block 4 and a hard board 5 having a circuit composed of electric elements and the like.
, A not-shown battery, a not-shown recording device, a not-shown strobe, and an extension lens barrel 6.

The structure of the extension type lens barrel 6 in such a digital camera will be described.

Reference numeral 7 denotes a CCD as an image sensor, and 8 denotes a low-pass filter, which are fixed to a base 9 respectively.

The base 9 is provided with a third group holder 11 for holding the third group lens 10 and a lens feeding mechanism 12 including a step motor and a screw feeder. The third group is operated by the operation of the lens feeding mechanism 12. Driven in the optical axis direction.

Reference numeral 13 denotes a fixed cylinder having a cam groove 13a and a straight key groove 13b formed on the inner periphery thereof.
The fixed cylinder 13 is fixed to the base 9.

Numeral 14 denotes a drive ring which is fitted on the outer periphery of the fixed cylinder 13 and rotates around the optical axis. The drive ring 14 is rotatably driven by a gear train 15 and a lens barrel driving device such as a lens barrel motor (not shown) connected to a gear portion 14 a provided on the outer periphery thereof. The drive ring 14 has a drive key groove 14b on the inner periphery thereof.

A cam cylinder 16 is provided on the inner periphery of the fixed cylinder 13. A cam pin 16a which engages with the cam groove 13a of the fixed cylinder 13 and a drive ring 1
4 and a drive pin 16b that engages with the drive key groove 14b. A first group cam groove 16c and a second group cam groove 16d are formed on the inner periphery of the cam cylinder 16.

When the drive ring 14 rotates, the drive key groove 1
The cam cylinder 16 is driven in the optical axis direction along the cam groove 13a while rotating by the engagement between the driving pin 4b and the driving pin 16b.

Reference numeral 17 denotes a rectilinear cylinder fitted on the inner periphery of the cam cylinder 16, and this rectilinear cylinder 17 has a rectilinear key portion 17a which engages with the rectilinear key groove 13b of the fixed cylinder 13. In addition, the cam barrel 16 is sandwiched in the optical axis direction by bayonet claws 17b and flanges 17c provided at both ends of the rectilinear motion cylinder 17 in the optical axis direction.
Moves together with the cam barrel 16 without rotating in the optical axis direction.

The straight-moving cylinder 17 has three groups of straight-moving key grooves (straight-moving guide grooves) 17d penetrating the cylinder main body, and three two-group straight-moving keys penetrating the cylinder main body. A groove 17e is provided.

Reference numeral 21 denotes a first-group holding barrel (a lens holding cylinder referred to in the claims) for holding the first-group lens 18 closest to the object. The first-group holding barrel 21 is engaged with a first-group cam groove (a cam groove in the claims) 16c of the cam cylinder 16.
Pin portion (cam follower portion in claims) 21
a, and three straight key portions 21b that engage with the first group straight key groove portions 17d of the straight barrel 17. The pin 2
1a and the straight key portion 21b are arranged side by side (to overlap) in the lens barrel radial direction, and are integrally formed with the first group holding lens barrel 21.

Since the first-group holding barrel 21 is allowed to move only straight by the rectilinear barrel 17, it does not rotate with respect to the camera body with the rotation of the cam barrel 16, but along the first-group cam groove 16 c. It is driven and moves forward and backward with respect to the cam barrel 16 in the optical axis direction.

Here, a guide rail (rail portion in the claims) 17f extending in the optical axis direction is formed on the side surface (end surface in the lens barrel circumferential direction) of the first group straight key groove portion 17d.

On the other hand, a guide claw which can be engaged with the guide rail 17f in the lens barrel radial direction is provided on the straight key portion 21b of the first group holding lens barrel 21 which is engaged with the first group straight key groove portion 17d. (Claw-shaped portion) 21c is formed.

Reference numeral 19 denotes a lens barrier that protects the first lens group 18 when the lens barrel is housed.
Is a barrier drive device for driving the opening and closing of the device. The lens barrier 19 and the barrier driving device 20 include the first group holding barrel 2
1 is fixed to the front end.

Reference numeral 22 denotes a second group lens, and a second group holder 25
Is held in. Also, in the second group holder 25. A shutter blade 23 and a shutter driving device 24 are attached.

The second group holder 25 is provided with two cam pins 25a (not shown) which engage with the second group cam grooves 16d of the cam cylinder 16.
An urging pin 27 urged radially outward by an urging spring 26 to be pressed against the second group cam groove 16d;
Straight key portion 25 engaged with the second group straight key groove portion 17e of No. 7
b.

The second group holder 25 is allowed to move only in the optical axis direction by the second group straight key groove portion 17e, and does not rotate with respect to the camera body with the rotation of the cam barrel 16 without being rotated with respect to the camera body. , And moves forward and backward with respect to the cam barrel 16 in the optical axis direction.

The circuit of the hard substrate 5 includes a lens barrel driving device including a lens barrel motor (not shown) and a lens extension mechanism 12.
The shutter driving device 24 is electrically connected via a flexible printed circuit board 28.

In the digital camera using the lens barrel of the differential extension type constructed as described above, when the operating member of the exterior member 3 is operated from the non-use state shown in FIG. The lens barrel driving device is controlled by the above circuit, and the drive ring 14 is driven to rotate, so that the cam barrel 16 and the first group holding lens barrel 21 are driven forward and backward in the optical axis direction, and the second group holder 25 is driven by the light. Extend in the axial direction. Further, by controlling the lens extension mechanism 12, the third group lens 10 is driven, and the optical system is arranged in the use state shown in FIG.

When the release operation is performed in the use state, A
Exposure, image processing, and recording operations are performed by performing F and AE operations.

In the case where a shock in the optical axis direction is applied to the first lens group holding lens barrel 21 of the lens barrel configured as described above by dropping the camera or hitting the tip of the lens barrel in a use state, the conventional method is used. Then, the first-group holding barrel 21 is inclined or deformed, and the pin portion 2 provided on the first-group holding barrel 21 is
1a may come off the first group cam groove 16c of the cam cylinder 16, but in this embodiment, the guide rail 17
The engagement between the f and the guide claw 21c prevents the pin portion 21a from moving more than a predetermined amount (engagement play) toward the inner peripheral side. It is surely prevented.

In this embodiment, the guide rail 17
As shown in FIG. 2, the engagement surface between f and the guide claw 21 c is
When viewed in the optical axis direction (that is, a cross section orthogonal to the optical axis), the inner side is a tapered surface positioned closer to the optical axis.

The engagement surface can also function as an optical axis direction guide surface of the first lens group holding barrel 21. Therefore, the guide rail 17 is provided in the first group linear keyway 17d.
By providing f, the first group straight key groove portion 17d does not impair the original straight guide function, and the first group
Detachment from the group cam groove 16c can be reliably prevented.

In this embodiment, a lens barrel for a digital camera has been described. However, the present invention is not limited to a digital camera but can be applied to a lens barrel of a film camera or a video camera.

[0057]

As described above, according to the present invention,
A lens follower is provided with a cam follower portion and a straight-moving key portion arranged side by side in the lens barrel radial direction. Since it is formed in a shape that restricts movement in the radial direction, even if an external force in the optical axis direction acts on the lens holding cylinder and the cam follower tries to move (disengage) in the lens barrel radial direction with respect to the cam groove, it goes straight. The detachment can be reliably prevented by the movement restricting action between the key portion and the straight guide groove portion, and a lens barrel and a camera resistant to impact can be realized.

Further, the engaging surface between the claw-shaped portion provided on the straight-moving key portion and the rail portion provided on the straight-moving guide groove portion is formed to have a tapered surface when viewed in the optical axis direction (that is, the cross section orthogonal to the optical axis). If formed, the engagement surface can also serve as an optical axis direction guide surface of the lens holding cylinder,
The disengagement can be reliably prevented without impairing the function as the original straight guide groove.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a camera (in use) according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the camera (in a non-use state).

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a longitudinal sectional view of a conventional camera (in use).

FIG. 5 is a longitudinal sectional view of a conventional camera (non-use state).

FIG. 6 is a sectional view taken along line AA of FIG. 5;

FIG. 7 is a diagram showing a state where an impact is applied to a first-group holding barrel in a conventional camera.

[Explanation of symbols]

 1, 101: Camera body 9, 109: Base 11: Third group holder 13, 113: Fixed cylinder 14, 114: Driving ring 16, 116: Cam cylinder 16c, 116c: First group cam groove part 17, 117: Straight cylinder 17d, 117d: 1st group linear keyway 17f: guide rails 19, 119: lens barrier 21, 121: 1st group holding barrel 21a, 121a: pin 21c: guide claw 25, 125: 2nd group holder

Claims (6)

[Claims] A lens holding cylinder for holding a lens, and a cam cylinder provided with a cam groove for engaging the cam follower provided on the lens holding cylinder to apply a driving force to the lens holding cylinder in an optical axis direction. And a guide barrel provided with a straight guide groove that engages with a straight key portion provided in the lens holding barrel and guides the lens holding barrel in the optical axis direction. In the lens holding barrel, the cam follower portion and the rectilinear key portion are provided side by side in the lens barrel radial direction, and the rectilinear key portion and the rectilinear guide groove portion correspond to the cam groove portion of the cam follower portion. A lens barrel having a shape that restricts movement in the barrel radial direction. 2. A claw-shaped portion protruding in the lens barrel circumferential direction is formed in the straight-moving key portion, and the claw-shaped portion is engaged with the end surface in the lens barrel circumferential direction of the straight-moving guide groove in the lens barrel radial direction. The lens barrel according to claim 1, wherein a rail portion that can be extended in the optical axis direction is formed. 3. The lens barrel according to claim 2, wherein an engagement surface between the claw-shaped portion and the rail portion is formed to be a tapered surface when viewed in an optical axis direction. 4. The lens barrel according to claim 1, wherein the straight key portion and the straight guide portion are formed integrally with the lens holding barrel. 5. The lens barrel according to claim 1, wherein the lens holding barrel holds a lens closest to the object. 6. A camera comprising the lens barrel according to claim 1.